So You Went and Had a Seizure. Now what?
Why go and do a thing like that?
Not funny. No one wants seizures, of course. But this question is actually important, because the reason someone has a seizure is used to determine whether he or she needs to go on anticonvulsants—anti-seizure medication to prevent them.
Epilepsy, defined as a
“sudden change in behavior caused by electrical hypersynchronization of neuronal networks in the cerebral cortex,”
is diagnosed officially after two or more unprovoked (see below) seizures more than 24 hours apart. If this happens, there is the likelihood more seizures are coming1.
Often, getting them is a lifelong commitment, so things must be sorted out clearly on the front end. And even though they may not end up being a lifelong commitment, a commitment to anticonvulsants is always a mistake if that decision is wrong.
Should anticonvulsants be started after a first seizure?
If epilepsy is diagnosed after “two or more seizures,” can getting on anticonvulsants after a first seizure really be a mistake? Yes. After a first seizure it is important to determine whether it was provoked or unprovoked.
Provoked seizures occur due to a treatable illness (meningitis, drug or alcohol withdrawal, etc.) or an isolated event (head trauma).
Unprovoked seizures are caused by a true brain abnormality. This is the category epilepsy is assigned.
Treatable illnesses and isolated events causing provoked seizures are soon apparent from a thorough evaluation, but narrowing down the causes of an unprovoked seizure to a brain problem requires ruling out other things that can mimic it (“provoked causes):
- Fainting (syncope), from a vagal reaction, hyperventilation, sudden low blood pressure (hypotension), hypoglycemia, anemia, overwhelming sympathetic response (squeamish about seeing blood, for example)
- Cardiac arrhythmias
- “Mini-stroke” (TIA, or transient ischemic attack, which is temporary)
- Psychogenic non-epileptic seizures (PNES), different from epileptic seizures because
- Tend to happen in front of witnesses (for sympathy)
- Don’t happen in sleep (epileptic seizures do)
- More likely associated with stressful situations that make one want to “escape”
- More frequent than epileptic seizures
When a person presents for treatment after a first seizure, all of the above, except TIA and arrhythmias , are usually ruled out intuitively because they typically come with a history of the several occurrences—repeatedly, not a “first” episode. But the above—as well as the TIA and cardiac arrhythmia—are not epilepsy and shouldn’t prompt anticonvulsants.
Meeting the criteria for epilepsy (two or more over more than 24 hours) does two things: it makes certain the two occurrences aren’t part of the same episode, and it supports the likelihood of more seizures to come.
An EEG and a CT scan are in the bag of diagnostics, too: more information is always better than less, and especially an abnormal EEG—even with a normal CT, can clinch the assessment (noting that the EEG can be normal if a seizure isn’t actually caught “in the act”).
What if a patient falls short of the “two-or-more-seizures” criterion? What about the first (so far?) unprovoked seizure?
When provoked causes have been ruled out and all conclusions point to epilepsy, certainly the two-or-more-seizures rule is justification enough to begin anticonvulsants. But what about just one seizure—a true epileptic seizure, that is the first—or not!—of more to come? Will there be a second? More? Or only this one? When is it prudent to jump the gun after only one seizure?
This depends on many things, including patient preferences. For instance,
- What if the patient drives for a living? Operates heavy machinery? Is an avid swimming enthusiast? These may prompt a patient to commit to an anticonvulsant regimen.
- What are the side effects? Do they outweigh the potential benefit? Patients should be informed that the risk of another seizure is greatest early within the first two years2.
- What other medical conditions does the patient have? Simultaneous illnesses (“comorbidities”) can make treatment of epilepsy necessary, or alternately, medications for other conditions can make anticonvulsants risky. For instance, if a patient has kidney or liver disease, anticonvulsants normally excreted out of the system by the kidneys or detoxified by the liver could pose a risk of build-up and toxicity.
How do anticonvulsants work?
Most work by affecting the way sodium, calcium, and potassium flow into or out of the nerve cells (neurons), which affects their firing off to other nerve cells. In these ways, anticonvulsants can either inhibit excitatory neurons or excite inhibitory neurons (slow the fast, or quicken the slow).
What are common anticonvulsants?
Initially, a single agent is begun. There is no single best anticonvulsant, the choice based on many factors such as comorbidities, psychiatric considerations, allergic reactions, etc. Most patients respond to a single agent, but often it is necessary to add another, treating epilepsy with a combination rationale.
The earliest anticonvulsants:
- Oxcarbazepine: similar to Carbamazepine (Trileptal, Oxtellar)
- Zonisamide, usually as an add-on therapy (Zonegran)
- Lacosamide (Vimpat)
- Rufinamide (Banzel)
- Eslicarbazepine, similar to carbamazepine (Aption)
- Ethosuximide (Zarontin; usually limited to “absence” seizures)
- Tiagabine (Gabatril)
- Vigabatrin (Sabril)
- Benzodiazepines (Clobazam—Onfi; Clonazepam (Klonopin), Lorazepam (Ativan), diazepam (Valium)
- Perampanel (Ficompa)
- Valproate (Depakene)
- Felbamate (Felbatol)
- Topiramate (Topamax)
- Gabapentin (Neurontin)
- Pregabalin (Lyrica)
- Levetiracetam (Keppra)
- Brivaracetam (Briviact)
- Ezogabine (Potiga)
- Cannabinoids (marijuana): a continuing conundrum, as it is legal in many states but continues to be illegal on a federal level.
What are the side effects of anticonvulsants?
There is a wide range of side effects, from lowered amounts of vitamins (e.g., folic acid) and minerals (zinc) to psychosis. A neurologist will individualize treatment based on these considerations as they apply to a patient’s other medical considerations.
How can other illnesses impact the choice of anticonvulsants?
What about psychiatric co-morbidities? Some anticonvulsants have mood stabilizing properties (Depakene, lamotrigine, carbamazepine, oxcarbazepine), making them a good choice in things like bipolar depression. Some can worsen depression (phenobarbital, tiagabine, vigabatrin, topiramate) or even provoke psychosis.
The list of anti-seizure (anticonvulsant) medications is growing all the time. Although, as stated above, there is no perfect or “best” anticonvulsant, what currently is available offers a good choice range for persons with epilepsy which can be individualized for psychiatric considerations, socioeconomic or employment factors, sexual performance side effects, the presence of other medical illnesses, or even for adding additional anticonvulsants to a main choice that incompletely prevents seizures. A good neurologist will know which to choose initially, which to add secondarily if required, and whether anticonvulsants are necessary lifelong or not. People still die from seizures or at least compromise their quality of life from them, so when assessing the risk as compared to the life-benefit, continuing to have seizures is a poor second choice to committing to anticonvulsant therapy.
- Fisher RS, Acevedo C, Arzimanoglou A, et al. ILAE official report: a practical clinical definition of epilepsy. Epilepsia 2014; 55:475.
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